@spec roundn(float(), 0..15) :: float()

Round a float to precision decimal places.

A thin wrapper over Float.round/2, mainly useful for trimming the noise digits that trigonometry leaves behind when comparing or displaying results. Ties round away from zero, so 1.5 becomes 2.0 and -1.5 becomes -2.0.

float must be a float; an integer raises FunctionClauseError. precision must be an integer in 0..15; anything larger raises ArgumentError.

Examples

iex> AstroUtils.Math.roundn(1.23456, 2)
1.23

iex> AstroUtils.Math.roundn(1.23456)
1.2346

iex> AstroUtils.Math.roundn(:math.cos(:math.pi() / 2), 12)
0.0